Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Catalysis & Excited state. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Deuterium Isotope Effect on 4-Aminophthalimide in Neat Water and Reverse Micelles †

Abstract: Picosecond time-resolved emission of 4-aminophthalimide (4-AP) in neat water and D2O and in the water pool of aerosol OT reverse micelles in n-heptane is reported. It is proposed that in protic solvents 4-AP undergoes ultrafast solvent-mediated proton transfer and the emission originates from the proton-transferred species. The abrupt decrease in the emission quantum yield and lifetime of 4-AP in protic solvents is attributed to the reduction in the S1−S0 energy gap in the proton-transferred species. Nearly 4-fold increase in the emission quantum yield (φf) and lifetime (τf) of 4-AP is observed in neat D2O compared to water. This is ascribed to the retardation of the nonradiative S1 → S0 internal conversion processes on deuteration of the imide proton. In neat water or D2O the solvation dynamics is too fast to be detected using our picosecond setup. However, in the water pool of reverse micelles the relaxation of the water (or D2O) slows down appreciably. The initial component of the solvation dynamics in...

Adaptive changes in the kinetochore architecture facilitate proper spindle assembly.

Abstract: Mitotic spindle formation relies on the stochastic capture of microtubules at kinetochores. Kinetochore architecture affects the efficiency and fidelity of this process with large kinetochores expected to accelerate assembly at the expense of accuracy, and smaller kinetochores to suppress errors at the expense of efficiency. We demonstrate that on mitotic entry, kinetochores in cultured human cells form large crescents that subsequently compact into discrete structures on opposite sides of the centromere. This compaction occurs only after the formation of end-on microtubule attachments. Live-cell microscopy reveals that centromere rotation mediated by lateral kinetochore-microtubule interactions precedes the formation of end-on attachments and kinetochore compaction. Computational analyses of kinetochore expansion-compaction in the context of lateral interactions correctly predict experimentally observed spindle assembly times with reasonable error rates. The computational model suggests that larger kinetochores reduce both errors and assembly times, which can explain the robustness of spindle assembly and the functional significance of enlarged kinetochores.

Removal of toxic Cr(VI) by UV-active functionalized graphene oxide for water purification

Abstract: Extraction of hazardous heavy metals like As, Hg, Cd, Cr(VI), etc. for water purification is a great challenge. Exploiting the large surface area of graphene, in the present work, we have synthesized a UV-active 2,6-diamino pyridine–reduced graphene oxide (DAP–RGO) composite to remove Cr(VI) from acidic water solution. Here, the presence of an extra pyridinic-nitrogen lone pair facilitates the removal efficiency of excess Cr(VI) [500 mg L−1 in 3 h only] over reported results so far. In addition to that, the unique advantage of this UV-active material is the enhancement of removal efficiency by 18% at a higher pH value. We believe that this study will bring forth a new class of UV-active graphene based adsorbents with remarkably high removal efficiency for toxic heavy metals from waste-water in future.